1. Field of the Invention
The present invention relates to a technique in construction and reinforcement of a housing constituting a body frame of a working vehicle, which houses power transmitting devices such as a main clutch, a damper coupling and the like, interposed between an engine and a transmission casing so as to be united together, and a technique in disposing a steering column, which houses a steering shaft, and a changing apparatus, which changes the rotational movement of the steering shaft into the steering movement of front driven wheels, on the housing.
2. Related Art
Conventionally, for the purpose of integrally connecting a transmission casing to an engine of a tractor, a front end surface of a cylindrical or inversely U-like shaped housing constituting a body frame is fixed to a rear end surface of an engine and a rear end surface of the housing is fixed to a front end surface of a transmission casing. The housing is entirely formed by molding.
Japanese Laid Open Gazette Hei. 7-10014, describes an example of a conventional technique for supporting a steering unit where a lower portion of a cylindrical steering column, rotatably housing a steering shaft, is fixed onto a support bracket, and an upper surface of a hydraulic control unit, which supplies operating oil to a power steering hydraulic cylinder proportionally to the rotation of the steering shaft, is fixed to the lower surface of the support bracket.
A molded frame disposed between the engine and the transmission casing according to the former of the above conventional techniques is disadvantageous in that extra time and cost are required to produce the mold and the molded frame adds too much weight to the working vehicle. Alternatively, if the engine and the transmission casing are connected through a sheet metal frame, complicated sheet metal processing and construction are required, because sheet metal, which is simply bent to be cylindrical or inversely U-like shaped, lacks strength.
A support bracket, onto which the lower portion of the steering column and the upper surface of the hydraulic control unit are fixed, according to the latter conventional technique is also lacking in strength, because it is made of a plate, extending from and supported on one side by a panel frame disposed in a dashboard. Also, the upper portion of the steering column is supported by and fixed to a panel frame, so that the supporting point of the steering column tends toward a high position. Thus, the steering unit lacks stability and is liable to swing. Furthermore, the supporting members, which support the steering unit, are not used to reinforce the clutch housing.